Well he certainly has stiff competition (most notably Donald Luskin (see here and here), but this NY Times column puts Sir Thomas directly in the running.
His argument is that "Red China has decided to become Green China" and since (according to him) going green is a zero sum game, they are going to bury stupid dumb corrupt America under a green on red avalanche:
Unfortunately, we’re still not racing. It’s like Sputnik went up and we think it’s just a shooting star. Instead of a strategic response, too many of our politicians are still trapped in their own dumb-as-we-wanna-be bubble, where we’re always No. 1...
There are, as you might imagine, a few problems with his argument. First off, he has no evidence that China has actually decided to go green. He mentions exactly two things. (1) An American "solar equipment maker" has opened a research center in China, and (2) A Chinese solar panel manufacturer told him that the party secretary of the town where the company is located told the Chinese business man that he wanted the party to support the business.
Even dumber than the notion that China, the world's biggest polluter, has gone green is the notion that going green is a zero sum competition. Friedman doesn't even try to argue for this point, he simply assumes it as self evident.
Friedman does find another idiot to quote here:
“If they invest in 21st-century technologies and we invest in 20th-century technologies, they’ll win,” says David Sandalow, the assistant secretary of energy for policy.
He then concludes, in classic stupidest man fashion, by completely undercutting his argument:
Of course, China will continue to grow with cheap, dirty coal, to arrest over-eager environmentalists and to strip African forests for wood and minerals. Have no doubt about that. But have no doubt either that, without declaring it, China is embarking on a new, parallel path of clean power deployment and innovation. It is the Sputnik of our day. We ignore it at our peril.
My conclusion: Thomas Friedman is a prime challenger for the position of stupidest man alive. We ignore him at our comedic peril.